Levator ani subtended volume: a novel parameter to evaluate levator ani muscle laxity in pelvic organ prolapse.

OBJECTIVE We describe a new parameter based on magnetic resonance 3-dimensional (3D) reconstructions proposed to evaluate levator ani muscle (LAM) laxity in women with pelvic organ prolapse (POP). STUDY DESIGN This is an institutional review board-approved, retrospective chart review of 35 women with POP, stages I-IV. The 3D Slicer software package was used to perform 2-dimensional and 3D measurements and the levator ani subtended volume (LASV) was described. Basically, the LASV represents the volume contained by LAM between 2 planes, which coincides with pubococcygeal line and H line. Correlations among measurements, ordinal POP stages, POP Quantification (POPQ) individual measurements, and validated questionnaires were performed. RESULTS The LASV differentiated major (III and IV) from minor (I and II) POPQ stages, which positively correlated to POP stages and POPQ individual measurements. CONCLUSION The LASV is a promising parameter to evaluate the LAM laxity.